Fixes compilation error with Xcode 8:
cannot initialize a parameter of type 'id<NSApplicationDelegate> _Nullable' with an lvalue of type 'ApplicationController *'
- Worked aorund modern GCC bug where C++ exceptions in Objective-C++ code would result in an ICE (bug is already on their tracker, but I doubt it will be fixed unless I decide to dig into the issue myself).
- Turn off fused floating point instructions since these can cause slight deviations in floating point code.
- Use -static-libgcc when compiling on the Mac with GCC since we need to use a custom version of GCC to do so now.
- Note: ZDoom will currently still crash on exit on PowerPC since it seems to be deciding that NameManager needs to be destructed before the console commands.
